Retention mechanism for an implantable lead

ABSTRACT

A retention device for use with an implantable medical device (IMD) are disclosed. An illustrative retention device may comprise an elongate body including a configured to receive the lead of the IMD. The retention device may also include securing mechanisms coupled to the elongate body and configured to push against tissue of a patient. The securing mechanisms may also include linking elements coupled to the elongate body and a portion of the securing mechanisms.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of and priority to U.S.Provisional Patent App. No. 62/702,092, filed Jul. 23, 2018, titledRETENTION MECHANISM FOR AN IMPLANTABLE LEAD, the disclosure of which isincorporated herein by reference.

BACKGROUND

The subcutaneous implantable cardioverter-defibrillator (S-ICD System)from Boston Scientific is implanted, according to the original FDAlabeling thereof, with a subcutaneous lead extending from an implantedpulse generator in an axillary pocket, over the ribs to the xiphoidprocess, and then superiorly along the left side of the sternum. Theimplant method as originally approved calls for a suture sleeve fixationnear the xiphoid. To affix the suture sleeve at this location to thefascia requires looping a suture around the suture sleeve and attachmentof the suture to the fascia, through an incision near the xiphoid. Manyearly implantations used three incisions, one for the pulse generator,one at the xiphoid, and one at a superior location along the sternum,close to but inferior to the manubrium, where the tip of the lead wouldbe placed and secured by suturing to the fascia.

The suturing steps that are used to secure the lead in position relativeto the thorax may extend procedure time. It would be advantageous toreduce such suturing steps, not just to reduce procedure time butpotentially also to reduce the needed size of incisions, particularly atthe xiphoid incision. There is significant interest in reducingprocedure time and simplifying the implant procedure by avoiding suchsuture steps. Moreover, the multiple incisions called for in the S-ICDSystem implantation procedure raise risks of infection and leave smallbut visible scars. This has led to interest in simplification of theimplant procedure by reducing the number of incisions from 3 to 2, whilecontinuing to ensure the lead is anchored in a desired position.

New and alternative methods and devices for securing a lead, whether forthe S-ICD System or other devices, are desired.

OVERVIEW

The present inventors have recognized that a new and useful innovationmay include a retention device and method of using a retention devicefor aiding in the placement of a lead. Such a retention device may beplaced on a distal portion of a lead.

A first illustrative and non-limiting example is a retention device foruse with an implantable medical device (IMD) that may have a lead. Thelead may have a proximal end for coupling to a canister and a distalend. The retention device may include an elongate body that may have aproximal end, a distal end, and a hollow lumen extending from theproximal end to the distal end configured to receive the lead. Theretention device may also include one or more securing mechanisms thatmay have a first end coupled to the elongate body, a second endconfigured to push against tissue of a patient, and an intermediateportion extending between the first and second ends. The retentiondevice may also include one or more first linking elements that may havea first end coupled to the elongate body and a second end coupled to theintermediate portion of one of the securing mechanisms.

Additionally or alternatively to the first illustrative, non-limitingexample, the retention device may have at least two securing mechanismsand further comprise one or more second linking elements, the one ormore second linking elements may have a first end coupled to a first oneof the securing mechanisms and a second end coupled to a second one ofthe securing mechanisms.

Additionally or alternatively to any of the above, non-limitingexamples, the at least two securing mechanisms may comprise a pluralityof securing mechanisms circumferentially spaced about the elongate bodyand the second linking elements link together adjacent ones of thesecuring mechanisms.

Additionally or alternatively to any of the above, non-limitingexamples, the first and second linking elements may be configured toprevent prolapse of the securing mechanisms.

Additionally or alternatively to any of the above, non-limitingexamples, the first linking elements may be configured to limit theextension of the second end of the one or more securing mechanisms awayfrom the elongate body.

Additionally or alternatively to any of the above, non-limitingexamples, the one or more securing mechanisms may be configured formovement between a delivery configuration, in which the securingmechanisms may be collapsed toward the elongate body, and a deployedconfiguration in which the linking element stops the one or moresecuring mechanism from extending beyond a predefined angle relative tothe elongate body.

Additionally or alternatively to any of the above, non-limitingexamples, the predefined angle is in the range of about 10 to about 60degrees.

A second illustrative and non-limiting example is a retention device foruse with an implantable medical device (IMD) that may have a lead. Thelead may have a proximal end for coupling to a canister and a distalend. The retention device may include an elongate body that may have aproximal end, a distal end, and defining a hollow lumen extending fromthe proximal end to the distal end configured to receive the lead. Theretention device may also include two or more securing mechanisms andeach may have a first end coupled to the elongate body, a second endconfigured to push against tissue of a patient, and an intermediateportion extending between the first and second ends. The retentiondevice may also include one or more first linking elements that may havea first end coupled to a first one of the securing mechanisms and asecond end coupled to a second one of the securing mechanisms.

Additionally or alternatively to any of the above, non-limitingexamples, the two or more securing mechanisms may comprise a pluralityof securing mechanisms circumferentially spaced about the elongate bodyand second linking elements link together adjacent ones of the securingmechanisms.

Additionally or alternatively to any of the above, non-limitingexamples, the flexible material may comprise a polymeric material.

Additionally or alternatively to any of the above, non-limitingexamples, the flexible material may comprise silicone.

A third illustrative and non-limiting example is a retention device foruse with an implantable medical device (IMD). The retention device mayinclude an elongate body having a proximal end, a distal end, a hollowlumen extending from the proximal end to the distal end and may beconfigured to receive a lead of the IMD. The retention device mayfurther include one or more securing mechanisms may have a first endthat may be configured to bend such that a portion of the one or moresecuring mechanisms extends to a predefined angle relative to theelongate body, wherein the one or more securing mechanisms may include asecond end that may be configured to extend to the predefined angle andpush against tissue of a patient, and wherein the elongate body may begenerally tubular with the securing mechanisms formed from a cut portionof the tube.

Additionally or alternatively to any of the above, non-limitingexamples, the cut portion of the tube may be located between theproximal and distal ends thereof.

Additionally or alternatively to any of the above, non-limitingexamples, the cut portion of the tube may be located at an end thereof.

Additionally or alternatively to any of the above, non-limitingexamples, the one or more securing mechanisms may comprise nitinol, thenitinol may be adapted to assume a shape above the transitiontemperature thereof that facilitates anchoring in tissue.

A fourth illustrative and non-limiting example is an implantable medicaldevice system that may comprise an implantable pulse generator that maycomprise a canister housing operational circuitry adapted to generate atherapy output, a lead adapted for coupling to the implantable pulsegenerator and adapted to deliver the therapy output from the implantablepulse generator, and a retention device as in any of the precedingexamples, wherein the lead may be sized and shaped to be received in thehollow lumen of the retention device.

A fifth illustrative and non-limiting example is a method of implantingan implantable lead that may have a first end for coupling to animplantable medical device and a second end for implantation at a targetsite in the patient, with a lead body extending therebetween. The methodmay comprise the use of a retention device as in any of the aboveexamples. The method may include inserting the implantable lead into thepatient with the retention device placed on the lead at a desiredlocation thereon and with a sheath disposed about at least a portion ofthe lead and compressing the one or more securing mechanisms of theretention device in a delivery configuration. The method may alsoinclude at least partly withdrawing the sheath such that the one or moresecuring mechanisms extend to a deployed configuration to anchor theimplantable lead to tissue of the patient.

Additionally or alternatively to the fifth illustrative, non-limitingexample, the step of inserting the implantable lead may be performed bymaking a first incision and a second incision, making a first tunnelbetween the first and second incisions, making a second tunnel from thesecond incision to an end location, and passing at least the second endof the implantable lead through the second incision to the end location,wherein the step of inserting the implantable lead may be performed suchthat the retention device may be accessible near the second incision,and the method may further comprise positioning the retention devicenear a xiphoid of the patient and partly withdrawing the sheath allowingthe one or more securing mechanisms to extend to the deployedconfiguration and push against tissue of the patient near the secondincision to secure the lead in a selected position.

A sixth illustrative and non-limiting example is a retention device foruse with an implantable medical device (IMD). The retention device maycomprise an elongate body having a proximal end, a distal end, a hollowlumen extending from the proximal end to the distal end that may beconfigured to receive a lead of the IMD. The retention device mayfurther include one or more securing mechanisms that may have a firstend that may be configured to bend such that a portion of the one ormore securing mechanisms extends to a predefined angle relative to theelongate body.

Additionally or alternatively to any of the above, non-limitingexamples, the one or more securing mechanisms may include a second endthat may be configured to extend to the predefined angle and pushagainst tissue of a patient.

Additionally or alternatively to any of the above, non-limitingexamples, the elongate body may be generally tubular with the securingmechanisms formed from a cut end of the tube.

Additionally or alternatively to any of the above, non-limitingexamples, the elongate body may be generally tubular with the securingmechanisms formed from a cut portion of the elongate body locatedbetween the proximal and distal ends thereof.

Additionally or alternatively to any of the above, non-limitingexamples, the one or more securing mechanisms may further include asecond end that may be configured to bend to the predefined angle in anopposite direction as the predefined angle from the bend of the firstend, and an intermediate section between the first end and the secondend that may be configured to extend away from the elongate body andpush against tissue of a patient.

Additionally or alternatively to any of the above, non-limitingexamples, the intermediate section may further include a bend.

Additionally or alternatively to any of the above, non-limitingexamples, each of the one or more securing mechanisms may be capable ofshifting between a delivery configuration and a deployed configuration.

Additionally or alternatively to any of the above, non-limitingexamples, in the deployed configuration the first end may be bent andthe one or more securing mechanisms may be extended to the predefinedangle relative to the elongate body.

Additionally or alternatively to any of the above, non-limitingexamples, the predefined angle may be in the range of about 10 to about60 degrees.

Additionally or alternatively to any of the above, non-limitingexamples, the one or more securing mechanisms may comprise a pluralityof securing mechanisms circumferentially spaced from one another, withgaps separating the plurality of securing mechanisms.

Additionally or alternatively to any of the above, non-limitingexamples, the gaps may be non-constant such that there is a largerdistance separating first ends of adjacent securing mechanisms, from theplurality of securing mechanisms, than second ends of the adjacentsecuring mechanisms.

Additionally or alternatively to any of the above, non-limitingexamples, the one or more securing mechanisms may be made of a flexiblematerial.

Additionally or alternatively to any of the above, the flexible materialmay comprise nitinol.

A seventh illustrative and non-limiting example is an implantablemedical device system that may comprise an implantable pulse generatorthat may comprise a canister housing operational circuitry adapted togenerate a therapy output, a lead adapted for coupling to theimplantable pulse generator and adapted to deliver the therapy outputfrom the implantable pulse generator, and a retention device as in anyof the above non-limiting examples, wherein the lead may be sized andshaped to be received in the hollow lumen of the retention device.

A eighth illustrative and non-limiting example is a method of implantingan implantable lead in a patient that may comprise the use of animplantable lead that may have a first end for coupling to animplantable medical device and a second end for implantation at a targetsite in the patient, with a lead body extending therebetween and aretention device for use with an implantable medical device (IMD), theretention device as in any of the above non-limiting examples. Themethod may include inserting the implantable lead into the patient withthe retention device placed on the lead at a desired location thereonand with a sheath disposed about at least a portion of the lead andcompressing the one or more securing mechanisms of the retention devicein a delivery configuration. The method may also include at least partlywithdrawing the sheath such that the one or more securing mechanismsextend to a deployed configuration to anchor the implantable lead totissue of the patient.

Additionally or alternatively to the eighth illustrative, non-limitingexample, the step of inserting the implantable lead may be performed bymaking a first incision and a second incision, making a first tunnelbetween the first and second incisions, making a second tunnel from thesecond incision to an end location, and passing at least the second endof the implantable lead through the second incision to the end location,wherein the step of inserting the implantable lead may be performed suchthat the retention device may be accessible near the second incision,and the method may further comprise positioning the retention devicenear a xiphoid of the patient and partly withdrawing the sheath allowingthe one or more securing mechanisms to extend to the deployedconfiguration and push against tissue of the patient near the secondincision to secure the lead in a selected position.

Additionally or alternatively to any of the above, non-limitingexamples, the implantable lead may be inserted through at least one ofthe tunnels by advancing a portion of the implantable lead into andthrough a sheath that has already been placed in the tunnel.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The drawings illustrate generally, by way of example, butnot by way of limitation, various embodiments discussed in the presentdocument.

FIGS. 1A-1B show a first example retention device;

FIG. 1C shows the first example retention devices coupled to a lead;

FIG. 1D shows an alternative design for the first example retentiondevice;

FIG. 2A shows the first example retention device in a deliveryconfiguration;

FIG. 2B shows the first example retention device in a deployedconfiguration;

FIGS. 3A-3B show a second example retention device;

FIG. 3C shows the second example retention devices coupled to the lead;

FIG. 4A shows the second example retention device in a deliveryconfiguration;

FIG. 4B shows the second example retention device in a deployedconfiguration;

FIGS. 5A-5B show a third example retention device;

FIG. 5C shows the third example retention devices coupled to the lead;

FIG. 6A shows the third example retention device in a deliveryconfiguration;

FIG. 6B shows the third example retention device in a deployedconfiguration;

FIGS. 7A shows a fourth example retention device in a deliveryconfiguration;

FIGS. 7B shows the fourth example retention device in a deployedconfiguration;

FIGS. 7C shows an alternative version of the fourth example retentiondevice in a deployed configuration;

FIGS. 8A shows a fifth example retention device in a deliveryconfiguration;

FIGS. 8B shows the fifth example retention device in a deployedconfiguration;

FIGS. 8C shows an alternative version of the fifth example retentiondevice in a deployed configuration;

FIGS. 9A shows a sixth example retention device in a deliveryconfiguration;

FIGS. 9B shows the sixth example retention device in a deployedconfiguration;

FIG. 10 shows the fourth example retention devices coupled to the lead;

FIGS. 11A-11C illustrate a first method for implanting an implantablemedical device;

FIGS. 12A-12E illustrate a second method for implanting the implantablemedical device; and

FIG. 13 is a block flow diagram for an illustrative method.

DETAILED DESCRIPTION

The following detailed description should be read with reference to thedrawings. The drawings, which are not necessarily to scale, depictillustrative embodiments and are not intended to limit the scope of theinvention. Any references to other patents or patent applications areintended as illustrative of useful methods or devices and are notintended to foreclose suitable alternatives. In the methods shown below,structures may be beneath the skin and over the ribcage of the patient,though such elements are not always shown in phantom. Some examples mayplace devices in the abdomen, again making use of anchoring techniquesthat secure to the fascia.

The words “proximal” and “distal” are used herein to differentiate theends of devices. No specific anatomical significance is intended. Forexample, the distal end of a lead is not necessarily anatomically distalrelative to the proximal end of the lead; anatomic distal and proximalposition will be determined by the final implantation location(s).

FIG. 1A depicts an illustrative side-view of an example retention device100 and FIG. 1B depicts an illustrative isometric-view of the exampleretention device 100. As shown, the retention device 100 may include anelongate body 102 and securing mechanisms 104A-104C spacedcircumferentially around the elongate body 102. In some cases, theelongate body 102 may have a hollow lumen 106 that extends from an opendistal end 108 to an open proximal end 110. In an example, the hollowlumen 106 is dimensioned to receive a portion of an implantable leadtherein. The elongate body 102 may be formed from any material suitablefor chronic implantation in patients, such as a wide variety of plasticsand/or metals. Different parts may be made of different materials, ormay have additional structure, such as by using coated wires for thesecuring mechanisms and an extruded tube for the elongate body, or theentire piece may be formed in a single molding step of a singlematerial.

The securing mechanisms 104A-104C are designed for securing the device100 in a patient's tissue, such as in the subcutaneous space over theribcage, or elsewhere. In some cases, the securing mechanisms 104A-104Care solely relied upon to anchor the device 100 to tissue of a patient;in other examples, a suture may also be used to augment securing forcetemporarily or permanently. While one set of securing mechanisms isshown, in other examples, there may be multiple sets of securingmechanisms spaced longitudinally along the elongate body 102.

In some cases, the securing mechanisms 104A-104C may be flaps that are aformed, single-piece with the elongate body 102 such as by injectionmolding or insert molding the entire piece onto a wire “skeleton”.Alternatively, the securing mechanisms 104A-104C may have first ends112A-112C coupled to the elongate body 102 in any suitable manner, whichmay include hinges, screws, pins and/or any other suitable fastener. Insome cases, the first ends may be molded onto the elongate body 102.

In some cases, the securing mechanisms may be configured to shift orflex so that second ends 114A-114C of the securing mechanisms 104A-104Cmove, retract, or compress towards the elongate body 102 to a deliveryconfiguration. In some cases, the securing mechanisms 104A-104C may befurther configured to shift or flex so that the second ends 114A-114Cmove, swing, or extend away from the elongate body 102 to a deployedconfiguration. While in a deployed configuration, the second ends114A-114C may be configured to push against the tissue of the patientwhen the retention device 100 is implanted in the patient.

The securing mechanisms may further comprise intermediate portions116A-116C extending between the first and second ends. In the exampleshown, linking elements 118A-118C have first ends 120A-120C coupled tothe elongate body 102 and second ends 122A-122C coupled to theintermediate portions 116A-116C of the securing mechanisms 104A-104C.The linking elements 118A-118C are flexible to allow the securingmechanisms to be compressed to their delivery configuration. In somecases, the linking elements 118A-118C may also have intermediateportions 124A-124C that include joints or bends configured to flex orshift and allow the securing mechanisms 104A-104C to move from thedelivery configuration to the deployed configuration and limit or stopthe securing mechanisms 104A-104C from moving beyond the deployedconfiguration. In some cases, because the securing mechanisms arereinforced by the linking elements to limit movement of the securingmechanisms while in the deployed configuration, the linking elements mayprevent prolapse of the securing mechanisms when the retention device100 is implanted within the patient.

In various examples, the securing mechanisms 104A-104C may be comprisedof the same materials as the elongate body 102. However, in some cases,the securing mechanisms 104A-104C may be comprised of differentmaterials than the elongate body 102. In certain embodiments, thesecuring mechanisms 104A-104C may be comprised of a different, stiffer,material than the elongate body 102. Alternatively, the securingmechanisms may be softer than the elongate body 102. In some examples,the securing mechanisms may be formed of silicone while a differentpolymer of stiffer or harder character is used for the elongate body102. In other examples, the securing mechanisms may be coated oruncoated nitinol or other metal, making them generally stiffer than theelongate body. Moreover, in some examples, the securing mechanisms104A-104C themselves may be comprised of different material (i.e., thelinking elements 118A-118C may be comprised of softer and/or moreflexible material than the rest of the securing mechanisms). In somecases, the securing mechanisms 104A-104C may be radiopaque.

According to various embodiments, the securing mechanisms 104A-104C maybe arranged to enable the retention device 100 to be collapsed by asheath to the delivery configuration. When the retention device 100 isin a selected position or configuration during implantation in thepatient, the sheath may be removed. Upon removal of the sheath, thesecuring mechanisms 104A-104C may expand at least in a radial directionto engage, push against, and/or anchor the retention device 100 in adesired location such as the subcutaneous tissue of a patient. In someexamples anchoring is desirable near the xiphoid of the patient, forexample. In other examples anchoring is desirable in a substernalimplantation position, wherein the anchoring apparatus is placed behindthe sternum in the mediastinum, preferably without contacting the heartor lungs.

In one example, a shape memory material is used for the securingmechanisms 104A-104C, such that the delivery configuration may beachieved with little tension exerted by the securing mechanisms104A-104C until body temperature is reached during implantation.Implantation may be performed using a sheath over the securingmechanisms 104A-104C to retrain them in the delivery configuration. Onceimplanted and with the insertion sheath removed, the shape memorymaterial can then cause the securing mechanisms to spring outward,anchoring to the surrounding tissue.

In some instances, the securing mechanisms 104A-104C may be tine shaped,hook shaped, fan shaped, a combination thereof, etc. Furthermore, thesecuring mechanisms 104A-104C may have rounded second ends 114A-114C toencourage tissue anchoring without piercing through the skin or othersensitive anatomical structures. In other embodiments, the second ends114A-114C may be square, pointed, convex, barbed, etc.

In some cases, as depicted in FIG. 1A and 113, there may be severalsecuring mechanisms 104A-104C that are circumferentially spaced from oneanother around the elongate body 102. In some cases, the securingmechanisms 104A-104C may be limited to one side of the elongate body102. In some instances, there may be a single securing mechanism 104A.

In some examples, the shapes of the securing mechanisms 104A-104C mayvary from one another. For example, different ones of the securingmechanisms 104A-104C may have different lengths or widths from oneanother. Some may be tapered, barbed, and/or pointed, while others mayhave a different shape such as being rounded. In some examples such asthat shown, the securing mechanisms 104A-104C, may all have the samewidth, length and shape.

In some examples, the securing mechanisms 104A-104C may be attached tothe elongate body 102. by the linking elements 118A-118C such that thesecuring mechanisms 104A-104C have a predefined desired degree ofangular separation with the elongate body 102 in the deployedconfiguration. For example, the linking elements may be configured tostop the securing mechanisms from extending beyond predefined angle ofseparation from the elongate body, in the range of about 10° to about60°, or in an example, about a 20° angle of separation with the elongatebody 102. In some cases, the angle of separation may be 15°, 30°, 45°,60° or more. In an example, the angle of separation may be less than90°, preventing prolapse.

In some cases, the angles of separation may be substantially the same orequal across each of the securing mechanisms 104A-104C, In some cases,the angles of separation may not be the same or equal to one another.Thus, while the examples shown generally have sets of securingmechanisms 104A-104C that are symmetrically placed about thecircumference of the retention device 100 with similar angular and shapecharacteristics, this need not be the case and different ones of thesecuring mechanisms 104A-104C may be differently oriented, sized orshaped, if desired. In addition, different ones of the securingmechanisms 104A-104C may have differing material properties, if desired.The various noted variations in shape, quantity, distribution, size,orientation, angular configuration, etc. may be incorporated in any ofthe following illustrative examples.

FIG. 1C depicts the example retention device 100 coupled to anillustrative implantable lead 130. In some cases, as shown in FIG. 1C,the retention device may be coupled to the implantable lead 130 byplacing the implantable lead 130 through the hollow lumen 106 of theretention device 100 such that the retention device 100 substantiallysumounds the lead 130, In some examples, the lead 130 may include ringelectrodes illustrated at 132A, 132B as well as coil electrode 134,though other electrode types and quantities may be used. For example, adirectional electrode array may be used. The lead 130 may bemanufactured of any suitable material and by any suitable manner. Asnoted above, a sheath may be disposed over the retention device 100prior to or during implantation.

FIG. 1D depicts an illustrative view of another example retention device150. As shown, the retention device 150 may include an elongate body 154and securing mechanisms 152 spaced circumferentially around the elongatebody 154, and a hollow lumen extending from an open distal end to anopen proximal end. Various elements of the materials, constructionand/or purpose of operation of the retention device 150 may be similarto that of the retention device 100. However, in this example, thesecuring mechanisms 152 may include linking elements 156 that may beelongate and configured to slide down into the hollow lumen such thatthe securing mechanisms 152 can fold down and lay relatively flatagainst the elongate body 154 when the retention device 150 is in thedelivery configuration. For instance, the elongate body 102 may includegaps or holes that extend from a surface of the elongate body 154 to thehollow lumen. Additionally, the linking elements 156 may have first endsthat fit into the gaps of the elongate body 154 and second ends coupledto the securing mechanisms 152. In some cases, the linking elements mayslide into the gaps of the elongate body 154 and into the hollow lumento allow the securing mechanisms to be compressed to their deliveryconfiguration. In some cases, the linking elements may also slide outfrom the hollow lumen to allow the securing mechanisms to move from thedelivery configuration to the deployed configuration. In some examples,the linking elements may be configured to stop from completely slidingout of the gaps and limit or stop the securing mechanisms from movingbeyond the deployed configuration. In some cases, because the securingmechanisms are reinforced by the linking elements to limit movement ofthe securing mechanisms while in the deployed configuration, the linkingelements may prevent prolapse of the securing mechanisms when theretention device 150 is implanted within the patient.

FIGS. 2A and 2B depict an illustrative example of the securingmechanisms 104A-104C moving the retention device 100 from the deliveryconfiguration (depicted in FIG. 2A) to the deployed configuration(depicted in FIG. 2B). As shown in FIG. 2A, when the securing mechanismsare collapsed by a sheath and/or shape memory techniques, to thedeployed configuration, the linking elements 118A-118C may bend orcollapse (as shown by arrows 202 and 204) such that the securingmechanisms lay relatively flat against the elongate body 102. Moreover,as shown in FIG. 2B, when the retention device 100 is at a desiredposition within the patient, the sheath may be removed and securingmechanisms may bend or expand to the deployed configuration (as shown byarrows 206 and 208) such that the securing mechanisms extend at least inthe radial direction to a predefined angle away from the elongate body,with the linking elements limiting the degree of separation of thesecuring mechanisms relative to the device body.

Referring to FIG. 1A and 2A, the intermediate joints or bends 124A-124Cmay be omitted in some embodiments. Rather than folding down as shown inFIG. 2A, the linking elements 118A-118C and securing mechanisms104A-104C may more or less wrap around the elongate body 102 to assume acollapsed configuration. The thickness, along the axial dimension of theelongate body, of the linking elements 118A-118C may be larger than thatshown. For example, the linking elements 118A-118C shown in FIG. 1A-1Chave a thickness in the axial direction 119 of the elongate body 102that is in the range of less than 10% of the length of the securingmechanisms 104A-104C. Thickness 119 may be, in other examples, in therange of 10% to 50% of the length of the securing mechanisms 104.

FIG. 3A depicts an illustrative side-view of another example retentiondevice 300 and FIG. 3B depicts an illustrative isometric-view of theexample retention device 300. As shown, the retention device 300 mayinclude an elongate body 302 and securing mechanisms 304A-304C spacedcircumferentially around the elongate body 302, and a hollow lumen 306extending from an open distal end 308 to an open proximal end 310.Various elements of the materials, construction and/or purpose ofoperation of the retention device 300 may be similar to that of theretention device 100. However, in this example, the securing mechanisms304A-304C may include linking elements 312A-312B that assist thesecuring mechanism to facilitate their purpose of operation. Forinstance, the linking elements 312A-312B may have first ends 314A-314Bcoupled to one of the securing mechanisms and second ends 316A-316Bcoupled to another securing mechanism (e.g., an adjacent securingmechanism). To some extend the design defines a web. In some cases, thelinking elements 312A-312B may also have intermediate portions 318A-318Bconfigured to bend or flex to allow the securing mechanisms 304A-304C tomove from the delivery configuration to the deployed configuration andlimit or stop the securing mechanisms 304A-304C from moving beyond thedeployed configuration. In some cases, because the securing mechanismsare reinforced by the linking elements and hold the securing mechanismsfrom moving beyond a desired angle in the deployed configuration, thelinking elements may prevent prolapse of the securing mechanisms whenthe retention device 300 is implanted within the patient. In anotherexample, the linking elements may help to push the securing mechanismsto the deployed position once a constraining sheath is removed.

FIG. 3C depicts the example retention device 300 coupled to anillustrative implantable lead 130. In some cases, as shown in FIG. 3C,the retention device may be coupled to the implantable lead 130 byplacing the implantable lead 130 through the hollow lumen 306 of theretention device 300 such that the retention device 300 substantiallysurrounds the lead 130 As noted above, a sheath may be disposed over theretention device 300 prior to or during implantation.

FIGS. 4A and 4B depict an illustrative example of the securingmechanisms 304A-304C moving the retention device 300 from the deliveryconfiguration (depicted in FIG. 4A) to the deployed configuration(depicted in FIG. 4B). As shown in FIG. 4A, when the securing mechanismsare collapsed by a sheath and/or shape memory techniques to the deliveryconfiguration, the linking elements 312A-312B may bend or collapse (asshown by arrows 402-408) such that the securing mechanisms layrelatively flat against the elongate body 302.

As shown in FIG. 4B, when the retention device 300 is at a desiredposition within the patient, the sheath may be removed and the linkingelements may straighten or expand to the deployed configuration (asshown by arrows 410-416) such that the securing mechanisms extend atleast in the radial direction to a predefined angle away from theelongate body. Alternatively, the securing mechanisms themselves mayreshape to adopt a deployed configuration, with the linking elementslimiting motion thereof to prevent prolapse.

FIG. 5A depicts an illustrative side-view of another example retentiondevice 500 and FIG. 5B depicts an illustrative isometric-view of theexample retention device 500. This example combines elements ofretention devices 100 and 300. The retention device 500 may include anelongate body 502, securing mechanisms 504A-504C spacedcircumferentially around the elongate body 502, and a hollow lumen 506extending from an open distal end 508 to an open proximal end 510. Theoverall material and purpose of operation of the retention device 500may be similar to that of the retention device 100 and 300. In thisexample, the securing mechanisms 504A-504C may include both linkingelements 512A-512C and 514A-514C that assist the securing mechanism tofacilitate their purpose of operation.

In the example, the linking elements 512A-512C may be coupled to thesecuring mechanisms and the elongate body and include joints or bendsconfigured to flex or shift and allow the securing mechanisms 504A-504Cto move from the delivery configuration to the deployed configurationand limit or stop the securing mechanisms 504A-504C from moving beyondthe deployed configuration. In addition, linking elements 514A-514B maybe coupled between two adjacent securing mechanisms and are configuredto bend or flex to allow the securing mechanisms 504A-504C to movebetween the delivery configuration and the deployed configuration. Thecombination of linking elements 512A-512C and the linking elements514A-514B and hold the securing mechanisms in a desired position,preventing prolapse while also keeping a larger profile of the overallanchoring structure than if, for example, the securing mechanisms couldall collapse to one side of the device. Meanwhile, as prolapse isprevented, and overall extension away from the elongate body 502 islimited, the individual ones of the securing mechanisms 504A-504C may beprevented from puncturing the skin or other nearby anatomy. Thus forexample, an anchoring device as depicted may be helpful in positions inthe mediastinum (such as for a substernal cardiac device) and/or nearthe spine (such as for a neuromodulation device or for a subcutaneousdefibrillator having a posterior lead), where nearby structures (heart,lung, and/or spinal cord) should be protected.

FIG. 5C depicts the example retention device 500 coupled to anillustrative implantable lead 130. In some cases, as shown in FIG. 5C,the retention device may be coupled to the implantable lead 130 byplacing the implantable lead 130 through the hollow lumen 506 of theretention device 500 such that the retention device 500 substantiallysurrounds the lead 130. As noted above, a sheath may be disposed overthe retention device 500 prior to or during implantation.

FIGS. 6A and 6B depict an illustrative example of the securingmechanisms 504A-504C moving the retention device 500 from the deliveryconfiguration (depicted in FIG. 6A) to the deployed configuration(depicted in FIG. 5B). As shown in FIG. 5A, when the securing mechanismsare collapsed by a sheath and/or shape memory techniques to the deliveryconfiguration, the linking elements 512A-512B and 514A-514B may bend orcollapse such that the securing mechanisms lay relatively flat againstthe elongate body 502. Moreover, as shown in FIG. 6B, when the retentiondevice 500 is at a desired position within the patient, the sheath maybe removed and the linking elements may straighten or expand as thesecuring mechanisms move to the deployed configuration. Force for suchexplanation to the deployed configuration may be provided by any of thesecuring mechanisms or linking elements.

FIG. 7A depicts an illustrative side-view of another example retentiondevice 700 in a delivery configuration. As shown, the retention device700 may include an elongate body 702 and securing mechanisms 704A-704C.In some cases, the retention device 700 may have a hollow lumen 706 thatextends from an open distal end 708 to an open proximal end 710. In anexample, the hollow lumen 706 is dimensioned to receive a portion of animplantable lead therein.

The retention device 700 may be formed from any material suitable forchronic implantation in patients, such as a wide variety of plastics,metals, and/or metal alloys, such as nitinol, for example. Differentparts may be made of different materials or additional structure of theretention device 700 may be produced using different techniques. Forinstance, a single nitinol piece having a generally tubular shape may besubject to laser cutting and austenite temperature shaping techniques tocut and/or form the securing mechanisms from an end of the tube. Invarious examples, the securing mechanisms 704A-704C may be comprised ofthe same materials as the elongate body 702. However, in some cases, thesecuring mechanisms 704A-704C may be comprised of different materialsthan the elongate body 702. In some instances, the securing mechanisms704A-704C may be comprised of a different, stiffer, material than theelongate body 702. Alternatively, the securing mechanisms may be softerthan the elongate body 702. Moreover, in some cases, the securingmechanisms 704A-704C may be radiopaque.

FIG. 7B depicts an illustrative side-view of the example retentiondevice 700 in a deployed configuration. In some cases, the securingmechanisms 704A-704C may have first ends 712A-712C configured to bendsuch that a portion of the securing mechanisms 704A-704C extend to apredefined angle relative to the elongate body 702. As shown in FIG. 7B,in this example, the securing mechanisms 704A-704C may extend around 20°relative to the elongate body 702. In some cases, the angle ofseparation may be in the range of about 10° to about 60°. In certainexamples, the angle of separation may be about 15°, 30°, 45°, 60°, or75°, for example. In some cases, the angles of separation may besubstantially the same or equal across each of the securing mechanisms704A-704C. In some cases, the angles of separation may not be the sameor equal to one another. In some cases, the securing mechanisms704A-704C may include second ends 714A-714C that may be configured toextend to the predefined angle and push against tissue of the patientwhen the retention device 700 is implanted in a patient. If desired, anouter web of intermediate pieces as shown above in the example of FIGS.3A-3B may be provided with the securing mechanisms 704A-704C.

FIG. 7C depicts an illustrative side-view of the example retentiondevice 700 in another deployed configuration. In some cases, the firstends 712A-712C of the securing mechanism 704A-704C may be configured tobend and extend intermediate sections 718A-718C of the securingmechanisms 704A-704C to a first predefined angle relative to theelongate body 702 and the intermediate sections 718A-718C may also bendand extend the second ends 714A-714C to a second predefined anglerelative to the elongate body 702. In some examples, the secondpredefined angle may be equal and opposite to the first predefinedangle. However, this does not have to be the case. As shown in FIG. 7C,in this example, the second ends 714A-714C may extend around ˜10°-20°relative to the elongate body 702. In some cases, the second angle ofseparation may be 15°, 30°, 45°, 60°, 90°, etc. In some cases, theangles of separation may be substantially the same or equal across eachof the second ends 714A-714C. In some cases, the angles of separationmay not be the same or equal to one another. In some cases, since thesecond ends 714A-714C may bend in the opposite direction of the firstends 712A-712, the intermediate sections 718A-718C may be configured topush against tissue of the patient when the retention device 700 isimplanted in the patient. This configuration may encourage tissueanchoring without piercing through the skin or other sensitiveanatomical structures since the extended intermediate sections may beless sharp the second ends of the securing mechanisms.

Turning back to FIG. 7A, as stated above, in some cases, the securingmechanisms 704A-704C may be flaps, leaflets, tines, hooks, fans, acombination thereof, etc. that are cut from the elongate body 702 suchthat the securing mechanisms 704A-704C are separated by gaps 716A-716B.In some examples, the gaps 716A-716B may be non-constant such that thefirst ends 712A-712C of the securing mechanism are separated by a largerdistance from one another than the second ends 714A-714C, but this doesnot have to be the case. Furthermore, the securing mechanisms 704A-704Cmay have rounded second ends 714A-714C to encourage tissue anchoringwithout piercing through the skin or other sensitive anatomicalstructures. In other examples, the second ends 714A-714C may be square,pointed, convex, barbed, etc. In some examples, the shapes of thesecuring mechanisms 704A-704C may vary from one another. For example,different ones of the securing mechanisms 704A-704C may have differentlengths or widths from one another. Some may be tapered, barbed, and/orpointed, while others may have a different shape such as being rounded.In some examples such as that shown, the securing mechanisms 704A-704Cmay all have the same width, length and shape, In some cases, asdepicted in FIGS. 7A.-7C, there may be several securing mechanisms704A-704C that are circumferentially spaced from one another around theelongate body 702. In some cases, the securing mechanisms 704A-704C maybe limited to one side of the elongate body 702. In some instances,there may be a single securing mechanism 704A. Thus, while the examplesshown generally have sets of securing mechanisms 704A-704C that aresymmetrically placed about the circumference of the retention device 700with similar angular and shape characteristics, this need not be thecase and different ones of the securing mechanisms 704A-704C may bedifferently oriented, sized or shaped, if desired. In addition,different ones of the securing mechanisms 704A-704C may have differingmaterial properties, if desired. The various noted variations in shape,quantity, distribution, size, orientation, angular configuration. etc.may be incorporated in any of the following illustrative examples.

In some cases, when austenite temperature shaping techniques are usedfor the securing mechanisms 704A-704C, once the retention device 700 isimplanted within the patient, the shape memory material can then causethe securing mechanisms 704A-704C to bend or flex at the first ends tothe first predefined angle to the deployed configuration, as depicted inFIG. 7B. In other cases, the shape memory material can cause thesecuring mechanisms 704A-704C to bend or flex at the first ends to thefirst predefined angle and bend or flex at the intermediate sections tothe second predefined angle to the deployed configuration, as depictedin FIG. 7C. In either deployed configuration, the retention device 700may then be anchored in a desired location such as the subcutaneoustissue of the patient or near a xiphoid of the patient, for example.

In another example, a device as shown in FIGS. 7A-7C may comprise anitinol or other metal base piece that is coated (for example, by spray,dip, overmold, etc.) with a polymer such as a silicone or other polymerthat may reduce trauma. Moreover, any of the examples shown herein maybe used in such a manner. Thus, for example, and without limitation, adevice as in FIGS. 1A-1D, or FIGS. 2A-2B, or FIGS. 3A-3C, or FIGS.4A-4B, or FIGS. 5A-5C, or FIGS. 6A-6B, or FIGS. 7A-7C, or FIGS. 8A-8C,or FIGS. 9A-9B, may include a coating, deposited by spray, dip, ormolding onto a wire skeleton or a formed or assembled piece, tube orsheet of Nitinol or other metal, or even onto a resilient polymer, toprovide a soft and biocompatible atraumatic exterior coating of siliconeor other polymeric material.

FIG. 8A depicts an illustrative side-view of another example retentiondevice 800 in a delivery configuration. FIG. 8B depicts an illustrativeside-view of the example retention device 800 in a deployedconfiguration. FIG. 8C depicts an illustrative side-view of the exampleretention device 800 in another deployed configuration. The retentiondevice 800 may be manufactured, configured, and operates similar to theretention device 700 and be implanted at similar locations within thepatient. However, the retention device 800 is an example of a retentiondevice that has more and narrower securing mechanisms.

FIG. 9A depicts an illustrative side-view of another example retentiondevice 900 in a delivery configuration. The retention device 900 may beconfigured similar to the retention device 700, however, securingmechanisms 904A-904C of the retention device 900 may be cut and/orformed from a midsection 920 of an elongate body 902.

FIG. 9B depicts an illustrative side-view of the example retentiondevice 900 in a deployed configuration. In some cases, first ends912A-912C of the securing mechanisms 904A-904C may bend or flex toextend intermediate sections 918A-918C to a first predefined anglerelative to the elongate body and second ends 914A-914C of the securingmechanism 904A-904C may be configured to bend or flex to extend theintermediate sections 718A-718C to a second predefined angle, oppositethe first predefined angle, relative to the elongate body 902. In someexamples, the second predefined angle may be equal to the firstpredefined angle. However, this does not have to be the case. As shownin FIG. 9B, in this example, the first and second predefined angles mayextend around about 10° to about 60° relative to the elongate body 902.In some cases, the first and second predefined angles may be 15°, 30°,45°, 60°, etc. In some cases, the angles of separation may besubstantially the same or equal across each of the securing mechanisms904A-904C. In some cases, the angles of separation may not be the sameor equal to one another. In some cases, since the first and secondpredefined angles may bend in the opposite directions, the intermediatesections 918A-918C may be configured to push against tissue of thepatient when the retention device 900 is implanted in the patient.

In some examples such as that shown, the securing mechanisms 904A-904Cmay all have the same width, length and shape. Thus, while the examplesshown generally have securing mechanisms 904A-904C that aresymmetrically placed about the circumference of the retention device 900with similar angular and shape characteristics, this need not be thecase and different ones of the securing mechanisms 904A-904C may bedifferently oriented, sized or shaped, if desired. In addition,different ones of the securing mechanisms 904A-904C may have differingmaterial properties, if desired. The various noted variations in shape,quantity, distribution, size, orientation, angular configuration, etc.may be incorporated in any of the following illustrative examples.

FIG. 10 depicts the example retention device 700 coupled to theillustrative implantable lead 130. In some cases, as shown in FIG. 10,the retention device may be coupled to the implantable lead 130 byplacing the implantable lead 130 through the hollow lumen 706 of theretention device 700 such that the retention device 700 substantiallysurrounds the lead 130. In some cases, a sheath may be disposed over theretention device 300 prior to or during implantation.

Various implantation techniques may be used with the anchoring systemsare shown above. Two examples for implantation of a subcutaneous-onlydefibrillator follow; other implementations are contemplated as well.For example, an anchoring device as shown above may be used to secure asingle or multiple coil subcutaneous lead electrode for use with atransvenous or epicardial cardiac therapy device. An anchoring device asshown above may be used to secure a lead for use with a spinal cordstimulation device. An anchoring device as shown may be used to secure alead near the implantable pulse generator (or on the neck) of a patienthaving a deep brain stimulation device. An anchoring device as shown mayalso be used to secure a lead for use in other neural or cardiacstimulus or therapy devices, without limitation.

FIGS. 11A-11C depict an illustrative one incision method of implantingan implantable medical device (IMD) in a patient 1100. In some cases,the implantable lead 130, having the retention device 100 disposedthereon, may be used. Beginning with FIG. 11A, certain anatomy of thepatient 1100 is highlighted including a heart 1102 and sternum 1104. Anaxillary incision may be made near the left axilla of the patient 1100,as shown at 1108. An insertion tool 1110 may be used in the procedure.The insertion tool 1110 may have a handle 1112 at a proximal end 1118,and an elongate shaft 1114 extends distally from the handle 1112 towarda distal dissecting tip 1120. The distal tip 1120 may be shaped fordissection of subcutaneous tissue. In one example, the distal tip 1120has a tapered blunt tip, allowing for passage by dissection throughsubcutaneous tissue without encouraging piercing through the epidermis.

A channel(s) may optionally be provided in the insertion tool 1110 toallow infusion of fluids for antiseptic, anti-inflammatory, painreduction, or other purposes at the dissecting tip or along the lengththereof. If ingrowth or adhesion is desired, a tissue adhesive orsteroid may be infused.

As shown by the arrow in FIG. 11A, the insertion tool 1110 may beinserted through the axillary incision 1108. In some cases, theinsertion tool 1110 may be deflectable or steerable and may be used tocreate a tunnel 1116 from the axillary incision 1108, just to the leftof and superior of the xiphoid near the lower portion of the sternum1104, and advanced generally parallel to the sternum 1104, as shown inFIG. 11B. In an example, the insertion tool 1110 is advanced as shownwith an introducer sheath thereon. The insertion tool 1110 may then bewithdrawn, keeping the introducer sheath in place.

In some cases, the lead 130 may be prepared for use by applying theretention device 100 thereon at a desired location such as by slidingthe retention device 100 over the proximal or distal end of the lead130. Alternatively, the lead 130 may be provided by the manufacturerwith the retention device 100 pre-attached and bonded to the lead 130,such as by using an adhesive, welding, heating, shrinking, orco-manufacturing process such as insert molding. The retention device100 may include a longitudinal slit to allow lateral placement onto alead, if desired. In some examples, a sheath may be placed over the lead130 and retention device 100 to aid in holding the retention device 100at the desired location on the lead, and to hold the securing mechanismsof the retention device in a delivery configuration, preventing themfrom engaging tissue during implantation prior to reaching a desiredimplant position.

As shown in FIG. 11C, the lead 130 may be positioned at a desiredlocation in the tunnel 1116 by insertion through the introducer sheath.Removal of the introducer sheath and the sheath placed over the lead 130(if one is used) then allows the retention device 100 to become engagedto the patient tissue at a desired location, such as near the xiphoid ofthe patient, as the securing mechanisms on the retention device 100expand from the delivery configuration to a deployed configuration. Atthe end of this step or prior to this step, a proximal plug 1126 of thelead 130 may be located relatively near the axillary incision 1108,though this may depend on the anatomy of the patient 1100 and the lengthof the lead 130. In some cases, the proximal plug or connector 1126 ofthe lead 130 may be attached to an implantable canister 1140. In somecases, the lead 130 coupled to the canister may comprise the IMD.

The canister 1140 may include a housing 1142 to house operationalcircuitry. For a cardiac electrical stimulus device, the operationalcircuitry may couple to the electrodes on the lead via conductors and beconfigured to analyze biological signals and deliver output therapy inthe form of at least one of bradycardia pacing, anti-tachycardia pacing,cardiac resynchronization therapy, or defibrillation, using theelectrodes on the lead 130. In other examples, non-cardiac therapyand/or stimulus may be provided such as by having a drug infusion pumpas the canister 1140 for infusing a drug or other substance for examplefor diabetes or pain management, and/or by having a neuromodulation orneurostimulation device adapted to deliver electrical stimuli to adesired body part to induce, modulate, or block signals and/oractivities; for example, spinal cord stimulation may be applied toalleviate or block pain, vagus nerve and/or deep brain stimulation maybe applied to address various conditions.

In the example shown, the canister 1140 may then be implanted throughthe axillary incision 1108 and sutured to the patient's 1100 tissue. Ifdesired, in addition to or as an alternative to suturing the canister1140 once positioned, a suture sleeve or retention device as shownherein may be provided in the axillary pocket to isolate the lead fromcanister motion. Having the IMD (including the lead 130) implanted withthe retention device 100 may provide several potential benefits. Forinstance, the retention device 100 may improve stability duringimplantation of the lead 130. The retention device 100 may also improvestability during acute implant duration, prior to tissue ingrowth. Insome cases, the retention device 100 may potentially improve long termstability, including a chance for less noise due to electrode movementand reduced inappropriate shocking. In some cases, the retention device100 may eliminate the need for suturing the lead down to the patientfascia. That is, a physician may implant the device without suturing theretention device 100 to the patient, instead relying on the securingmechanisms thereof to hold it in place and thus reducing the time neededfor implantation.

Several modifications may be made to the method of implanting the IMDdescribed in FIGS. 11A-11C. For example, rather than the steps of FIGS.11A-11C to place the lead 130 over the ribs and alongside the sternum, asubsternal approach may be taken by advancing the lead beneath the ribs.The lead may be directed to an entirely different location, such as nearthe spine, kidney, or elsewhere. The canister 1140 may be placedelsewhere as well, such as in the abdomen, near or in the buttocks, oradjacent or near the clavicle, or any other desired position.

In some cases, several alternative structures for leads and retentiondevices may be used and additional steps/features may be are provided.In some examples, the retention device may take the form of theretention devices 100, 300, 500, 700, 800, or 900. For instance, in thecase where the retention device 900 is used, the steps of positioningthe lead at a desired location in the tunnel 1116 and removing of thesheath placed over the lead 130 during implant may be similar to thesteps described above. The securing mechanisms can then move to theirdeployed configuration.

FIGS. 12A-12E depict an illustrative two incision method of implantingan IMD in the patient 1100. Similar to the one incision method shown inFIGS. 11A-11C, the implantable lead 130, having the retention device 100disposed thereon, may be used. Beginning with FIG. 12A, a xiphoidincision 1206 may be made just to the left of and superior of thexiphoid near the lower portion of the sternum 1104, and an axillaryincision may be made near the left axilla of the patient 1100, as shownat 1108. An insertion tool 1210 may be used in the procedure. Theinsertion tool 1210 may have a handle 1212 at a proximal end 1218, andan elongate shaft 1214 extends distally from the handle 1212 toward adistal dissecting tip 1220 that includes an attachment feature 1216. Theattachment feature 1216 is shown as a suture opening, however, othersuitable attachment features known in the art may be used. The distaltip 1220 may be shaped for dissection of subcutaneous tissue. In oneexample, the distal tip 1220 has a tapered blunt tip, allowing forpassage by dissection through subcutaneous tissue without encouragingpiercing through the epidermis. A channel(s) may be provided in theinsertion tool 1210 to allow infusion of fluids for antiseptic,anti-inflammatory, pain reduction, or other purposes at the dissectingtip or along the length thereof. If ingrowth or adhesion is desired, atissue adhesive or steroid may be infused as well. As shown by the arrowin FIG. 11A, the insertion tool 1210 may be inserted through the xiphoidincision 1206 and advanced toward the axillary incision 1108.

As shown in FIG. 12B, the lead 130 may be prepared similar to thedescription above in regard to FIGS. 11A-11C. In some cases, theinsertion tool 1210 may be inserted into the xiphoid incision 1206 untilits distal tip 1220, including the attachment feature 1216, can beaccessed through the axillary incision 1108. Then the suture 1222 may beused to attach the attachment feature 1216 of the insertion tool 1210 toan attachment feature 138 on a distal tip portion 136 of the lead 130.If needed, the lead 130 may be prepared by attaching a retention device100 (before or after attachment to the insertion tool 1210).Alternatively, the retention device 100 may be permanently attached tothe lead 130 during manufacturing thereof.

In some examples, a sheath may be placed on the lead, either at the timeof surgery or as a preloaded system, to prevent the retention device 100engaging tissue during its introduction into the patient. Next, theinsertion tool 1210 may be withdrawn through the xiphoid incision 1206,with the suture 1222 pulling the lead 130 into the patient'ssubcutaneous tissue through the axillary incision 1108. Alternatively, asheath may be used to advance the lead 130 into tissue without the useof the suture to pull the lead 130. The end of this pulling step isshown in FIG. 12C, where the attachment feature 138 at the distal tipportion 136 of the lead 130 extends through the xiphoid incision 1206and forceps (not shown) may be used to grasp the suture 1222, which maybe cut from the attachment feature 1216. At the end of this step, theproximal plug 1226 of the lead 130 may be located relatively near theaxillary incision 1108.

If used, a sheath may be removed after the lead has been pulled to andthrough the axillary incision. Alternatively, the sheath may be kept inplace until implantation is complete. In still other alternatives, nosheath is used during this tunneling and pulling step. For example, nosheath may be needed during pulling from the axillary incision to thexiphoid incision if the securing mechanisms are biased to allow passagethrough tissue in one direction but not the other.

In the example shown in FIG. 12C and as described herein, the distal tip1220 of the insertion tool 1210 may be shaped to allow for passage bydissection through subcutaneous tissue. Accordingly, the insertion tool1210 may be reinserted into the xiphoid incision 1206 and advancedgenerally parallel to the sternum 1104 to create a tunnel 1230, as shownin FIG. 12D. Though not shown, an introducer sheath may be placed overthe insertion tool 1210 during the step shown in FIGS. 12C-12D. Theinsertion tool 1210 may then be withdrawn, with the introducer sheathleft in place.

As shown in FIG. 12E, the lead 130 may be reinserted into the xiphoidincision 1206 and advanced generally through the tunnel 1230 andretained introducer sheath. The introducer sheath is then split andremoved over the lead. Removal of the introducer sheath allows theretention device 100 to engage the patient tissue at a desired location,such as near the xiphoid of the patient, as the securing mechanisms onthe retention device 100 expand from the delivery configuration to thedeployed configuration.

In some examples, if the introducer sheath is used in both passagethrough the axillary-xiphoid tunnel and in the parasternal tunnel, itwould be removed at the left axilla. If the introducer sheath is usedonly in the parasternal tunnel, or is removed after the passage fromaxilla to xiphoid and a second introducer sheath used for theparasternal tunnel, then the introducer sheath would be removed at thexiphoid. The proximal plug 1226 of the lead 130 may then be attached tothe canister 1140 and the canister 1140 may be implanted through theaxillary incision 1108 and sutured to the patient's 1100 tissue.

In some examples, a two incision, two sheath approach may be usedsimilar to that shown in U.S. Provisional Patent Application Ser. No.62/576,910. For example, a first tunnel from the axillary incision tothe xiphoid may be formed using a first insertion tool with a firstsheath thereon, with the first insertion tool then removed to leave thefirst sheath in place in the axillary-xiphoid tunnel. A second tunnelfrom the xiphoid incision to a desired position, such as near themanubrium, may be formed using a second insertion tool lead having asecond sheath thereon, with the second insertion tool then removed toleave the second sheath in place. The lead, having an anchoring orretention apparatus as shown herein attached or integral thereto may beadvanced into first and second sheaths in any order or direction, asdesired. For example, the proximal end of the lead may be passed throughthe first sheath from the xiphoid to the axilla, while the distal end ofthe sheath is then (or already has been) advance into the second sheath;once a desired position is achieved, both sheaths are removed to allowthe lead to become anchored in place. In another example, the distal endof the lead is passed through the first sheath from the axilla to thexiphoid, and then into the second sheath from the axilla to a desiredlocation; once a desired position is achieved, both sheaths are removedto allow the lead to become anchored in place. For such examples, thelead is passed through a subcutaneous tunnel by inserting a portionthereof into and through a sheath that has already been placed.

If desired, a three incision technique for subcutaneous defibrillatorimplantation may be used that may be generally similar, except withrespect to the use of the retention device, to certain examples in U.S.Pat. No. 7,655,014, titled APPARATUS AND METHOD FOR SUBCUTANEOUSELECTRODE INSERTION, the disclosure of which is incorporated herein byreference. Here, for example, the time spent suturing at the xiphoidincision may be reduced by using a retention device as shown herein atthat location; alternatively or additionally a retention device as shownherein may be used at the third incision—superior alongside the sternum.

In the various examples, shown, the end location for the retentiondevice 100 may be in several different spots. In some examples, theretention device 100 will be placed at the distal end of the lead andwill engage tissue more or less near the sternum superior to one or moreelectrodes of the lead 130. In other examples, the retention device 100will end up near the xiphoid process, inferior to the anatomicalposition of the electrodes on the lead 130. In other examples, theretention device 100 may be positioned along the inframammary crease.

At a high level, a single incision method may omit each of the xiphoidand sternal incisions; a sheath is used to secure the parasternal tunneland may additionally serve to support lead passage and/or to restrain orretain securing mechanisms on the lead. The present invention, for thesingle incision method, aids omission of at least the xiphoid incisionby providing anchoring at a desired location on the lead. The singleincision method may use a curved, telescoping and/or deflecting orsteerable tunneling system, such as in US PG Pat. Pub. No. 20170020551,titled MINIMALLY INVASIVE METHOD TO IMPLANT A SUBCUTANEOUS ELECTRODE,the disclosure of which is incorporated herein by reference. A singleincision method may also or instead use a method as shown in US PG Pat.Pub. No. 20190054302, titled SINGLE INCISION SUBCUTANEOUS IMPLANTABLEDEFIBRILLATION SYSTEM, the disclosure of which is incorporated herein byreference.

As illustrated in these examples, the present invention facilitatesflexibility in selection of the implant procedure. For example, with avery active or young patient where lead migration is a great concern, orfor a patient with a lot of adipose tissue that may make lead anchoringmore challenging, a multiple incision technique may be performed usingthe retention devices to hold the lead in place by multiple approaches.For other patients, a single incision technique may be used relyingsolely on the retention device, or a two incision technique that omits axiphoid incision relying on a retention device at an intermediatefixation point as well as, optionally, distal tip fixation by aretention device. Such flexibility may allow the physician to makechanges to the planned procedure intraoperatively, without having todiscard a lead that is deemed unsuitable to the particular patient. Aphysician may determine, through gentle tugging at the proximal (ordistal) end of the lead, whether additional retention devices need to beapplied.

FIG. 13 is a block flow diagram of an illustrative method 1300 forproviding an IMB system to a patient. As shown, the method 1300comprises establishing access in a patient and inserting a lead 1302,attaching an implantable pulse generator (IPG) to the lead 1310, andperforming test operations 1316. The IPG may also be referred to hereinas a canister or implantable canister.

For example, establishing access to the patient and inserting a lead1302 may include using a one incision implantation method, such asdescribed above relative to FIGS. 11A-11C as indicated at 1304. Inanother example, establishing access to the patient and inserting a lead1302 may include using a two incision implantation method 1306,generally as shown above relative to FIGS. 12A-12E. In another example,a three incision implantation method may be used to establish access tothe patient.

Regardless of the incision method used, once the lead is at a selectedposition or configuration in the patient, securing mechanisms located ona retention device of the lead may engage, push against, and/or anchorthe lead to the patient tissue, such as near the xiphoid of the patient.Suturing to the fascia may thus be reduced or omitted.

In an example, attaching an IPG to the lead 1310 may include attachingto a canister located in a subclavicular location 1312, historically acommon place to put an implanted canister for a transvenousdefibrillator or pacemaker. In another example, attaching to an IPG mayinclude attaching to a canister located in an axillary position 1314,such as that used with the S-ICD System. Other IPG locations may beused. Attachment may be directly to the IPG or to a splitter, yoke, orlead extension, if desired.

In an example, test operations 1316 may be used to verify one or both ofdevice functionality and efficacy. For example, sensing operations 1318may be tested and configured to check for adequate signal availability,for example, or by setting gain, filtering, or sensing vector selectionparameters. Defibrillation operations 1320 may be tested by inducting anarrhythmia such as a ventricular fibrillation to determine whether thedevice will sense the arrhythmia and, if the arrhythmia is sensed, toensure that the device can adequately provide therapy output bydelivering defibrillation at a preset energy. Defibrillation testing1320 may include determining for a given patient an appropriatedefibrillation threshold, and setting a parameter for therapy deliveryat some safety margin above the defibrillation threshold. For other,non-cardaic-electrical systems, (such as a drug pump or neuromodulationsystem), other therapy testing methods may be applied, as isconventional for those other products.

In an example, pacing testing operation 1322 may include determiningwhich, if any, available pacing vectors are effective to provide pacingcapture. If desired, parameters may be tested as well to determine andoptimize settings for delivery of cardiac resynchronization therapy.This may include testing of pacing thresholds to optimize energy usageand delivery, as well as checking that adverse secondary effects, suchas patient sensation of the delivered pacing or inadvertent stimulationof the phrenic nerve, diaphragm or skeletal muscles are avoided.

As noted above, the illustrative retention devices may be formed of anybiocompatible material. Some examples include elastic, biocompatiblealloys capable of forming stress induced martensite (SIM). Nitinol(TiNi) is an example of such materials. A retention device may be formedfrom stainless steel, such as high tensile stainless steel, or othermaterials, including metals and metal alloys, such as tungsten, gold,titanium, silver, copper, platinum, palladium, iridium, ELGILOYnickel-cobalt alloys, cobalt chrome alloys, molybdenum tungsten alloys,tantalum alloys, titanium alloys, etc. A retention device may be formedfrom a lubricious polymer, such as a fluorocarbon (e.g.,polytetrafluoroethylene (PTFE)), a polyamide (e.g., nylon), apolyolefin, a polyimide, or the like). A retention device may be formedof polyethylene, polyvinyl chloride (PVC), ethyl vinyl acetate (EVA),polyethylene terephthalate (PET), and their mixtures and copolymers.Another useful class of polymers is thermoplastic elastomers, includingthose containing polyesters as components. A retention device may alsobe comprised of such materials as soft thermoplastic material,polyurethanes, silicone rubbers, nylons, polyethylenes, fluorinatedhydrocarbon polymers, and the like. A retention device may also be of amember selected from a more flexible material such as low densitypolyethylene (LDPE), polyvinylchloride, THV, etc. Still in furtherembodiments, a retention device may be composed of a combination ofseveral these materials. In certain embodiments, a retention device maybe formed of, impregnated with, or comprise a maker made of a radiopaquematerial such as, for example and without limitation barium sulfate(BaSO4), bismuth trioxide (Bi2O3), bismuth subcarbonate (Bi2O2CO3),bismuth oxychloride (BiOCl), and tungsten.

Retention devices may be formed by molding, such as injection molding,or insert molding. In some examples, different parts or layers may beincluded such as by, for example, extruding a core tube having one or aplurality of layers (such as a lubricious inner layer with a tie layerthereon to allow ready attachment of additional material) of theretention device and insert molding an outer surface thereon of adifferent material, with the securing mechanisms added via the insertmolding process. In another example, a wire member may be used as astarting point for an insert molding process, wherein the wire membercomprises a set of tines to use as securing mechanisms on which apolymeric material is added.

Lead structures for use with the present invention may take any suitabletype and use any suitable material, such as the materials noted above.Internal longitudinal or lateral support members, such as braids, corewires, etc. may be provided. Extrusion or molding may be used for leadmanufacture. Internal conductors in the lead may be formed of anysuitable material (stainless steel, titanium, gold, silver, or any otherconductive material may be used) and may take any suitable form, such assimple wires, coated wires, braided or wound wires, drawn wires, and/ordrawn filled tubes, or other structures. The lead may include on all ora portion thereof various coatings such as an anti-microbial coating toreduce the likelihood, severity, and/or progression of infection.

The implantable systems shown above may include an implantable pulsegenerator (IPG) adapted for use in a cardiac therapy system. The IPG mayinclude a hermetically sealed canister that houses the operationalcircuitry of the system. The operational circuitry may include variouselements such as a battery, and one or more of low-power and high-powercircuitry. Low-power circuitry may be used for sensing cardiac signalsincluding filtering, amplifying and digitizing sensed data. Low-powercircuitry may also be used for certain cardiac therapy outputs such aspacing output, as well as an annunciator, such as a beeper or buzzer,telemetry circuitry for RF, conducted or inductive communication (or,alternatively, infrared, sonic and/or cellular) for use with anon-implanted programmer or communicator. The operational circuitry mayalso comprise memory and logic circuitry that will typically couple withone another via a control module which may include a controller orprocessor. High power circuitry such as high power capacitors, acharger, and an output circuit such as an H-bridge having high powerswitches may also be provided for delivering, for example,defibrillation therapy. Other circuitry and actuators may be includedsuch as an accelerometer or thermistor to detected changes in patientposition or temperature for various purposes, output actuators fordelivering a therapeutic substance such as a drug, insulin or insulinreplacement.

Some illustrative examples for hardware, leads and the like forimplantable defibrillators may be found in commercially availablesystems such as the Boston Scientific Teligen™ ICD and Emblem S-ICD™System, Medtronic Concerto™ and Virtuoso™ systems, and St. Jude MedicalPromote™ RF and Current™ RF systems, as well as the leads provided foruse with such systems. The present invention may be used for non-cardiacdevices such as, for example and without limitation, the Precision Noviand Precision Spectra neuromodulation devices offered by BostonScientific. Any suitable lead structure may be used, such as leadsadapted for subcutaneous implantation for cardiac monitoring or therapypurposes, and/or leads adapted for use in spinal, deep brain, orperipheral neuromodulation systems such as vagus or sacral nervetherapies. When used in a neuromodulation system, the methods of FIG. 13may be modified to swap out the test operations at 1316 to determiningappropriate therapy settings using methods well known in theneuromodulation field. The present invention may also be used inassociation with a drug pump that injects a fluid; rather than anchoringan electrical lead, a fluid injection catheter used by the drug pump maybe implanted and anchored in place.

The above detailed description includes references to the accompanyingdrawings, which form a part of the detailed description. The drawingsshow, by way of illustration, specific embodiments in which theinvention can be practiced. These embodiments are also referred toherein as “examples.” Such examples can include elements in addition tothose shown or described. However, the present inventors alsocontemplate examples in which only those elements shown or described areprovided. Moreover, the present inventors also contemplate examplesusing any combination or permutation of those elements shown ordescribed (or one or more aspects thereof), either with respect to aparticular example (or one or more aspects thereof), or with respect toother examples (or one or more aspects thereof) shown or describedherein.

In the event of inconsistent usages between this document and anydocuments so incorporated by reference, the usage in this documentcontrols. In this document, the terms “a” or “an” are used, as is commonin patent documents, to include one or more than one, independent of anyother instances or usages of “at least one” or “one or more.” Moreover,in the following claims, the terms “first,” “second,” and “third,” etc.are used merely as labels, and are not intended to impose numericalrequirements on their objects.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) may be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description. The Abstract is provided to complywith 37 C.F.R. §1.72(b), to allow the reader to quickly ascertain thenature of the technical disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims.

Also, in the above Detailed Description, various features may be groupedtogether to streamline the disclosure. This should not be interpreted asintending that an unclaimed disclosed feature is essential to any claim.Rather, inventive subject matter may lie in less than all features of aparticular disclosed embodiment. Thus, the following claims are herebyincorporated into the Detailed Description as examples or embodiments,with each claim standing on its own as a separate embodiment, and it iscontemplated that such embodiments can be combined with each other invarious combinations or permutations. The scope of the invention shouldbe determined with reference to the appended claims, along with the fullscope of equivalents to which such claims are entitled.

The claimed invention is:
 1. A retention device for use with animplantable medical device (IMD) having a lead, the lead having aproximal end for coupling to a canister and a distal end, the retentiondevice comprising: an elongate body having a proximal end, a distal end,and a hollow lumen extending from the proximal end to the distal endconfigured to receive the lead; and one or more securing mechanismshaving: a first end coupled to the elongate body; a second endconfigured to push against tissue of a patient; and an intermediateportion extending between the first and second ends; and one or morefirst linking elements having a first end coupled to the elongate bodyand a second end coupled to the intermediate portion of one of thesecuring mechanisms.
 2. The retention device of claim 1 having at leasttwo securing mechanisms, further comprising one or more second linkingelements, the one or more second linking elements having a first endcoupled to a first one of the securing mechanisms and a second endcoupled to a second one of the securing mechanisms.
 3. The retentiondevice of claim 2 wherein the at least two securing mechanisms arecircumferentially spaced about the elongate body and the second linkingelements link together adjacent ones of the securing mechanisms.
 4. Theretention device of any of claim 1, wherein the first linking elementsare configured to prevent prolapse of the securing mechanisms.
 5. Theretention device of claim 1 wherein the first linking elements areconfigured to limit the extension of the second end of the one or moresecuring mechanisms away from the elongate body.
 6. The retention deviceof claim 1 wherein the one or more securing mechanisms are configuredfor movement between a delivery configuration, in which the securingmechanisms are collapsed toward the elongate body, and a deployedconfiguration in which the linking element stops the one or moresecuring mechanism from extending beyond a predefined angle relative tothe elongate body.
 7. The retention device of claim 6 wherein thepredefined angle is in the range of about 10 to about 60 degrees.
 8. Theretention device of claim 1 wherein the retention device comprisessilicone.
 9. The retention device of claim 1 wherein the one or moresecuring mechanisms comprise nitinol, the nitinol adapted to assume ashape above the transition temperature thereof that facilitatesanchoring in tissue.
 10. An implantable medical device system comprisingan implantable pulse generator comprising a canister housing operationalcircuitry adapted to generate a therapy output, a lead adapted forcoupling to the implantable pulse generator and adapted to deliver thetherapy output from the implantable pulse generator, and a retentiondevice as in claim 1, wherein the lead is sized and shaped to bereceived in the lumen of the retention device.
 11. A retention devicefor use with an implantable medical device (IMD) having a lead, the leadhaving a proximal end for coupling to a canister and a distal end, theretention device comprising: an elongate body having a proximal end, adistal end, and defining a lumen extending from the proximal end to thedistal end configured to receive the lead; and two or more securingmechanisms each having: a first end coupled to the elongate body; asecond end configured to push against tissue of a patient; and anintermediate portion extending between the first and second ends; andone or more first linking elements having a first end coupled to a firstone of the securing mechanisms and a second end coupled to a second oneof the securing mechanisms.
 12. The retention device of claim 11 whereinthe two or more securing mechanisms are circumferentially spaced aboutthe elongate body and the first linking elements link together adjacentones of the securing mechanisms.
 13. The retention device of claim 11wherein the one or more securing mechanisms are configured for movementbetween a delivery configuration, in which the securing mechanisms arecollapsed toward the elongate body, and a deployed configuration inwhich the linking element stops the one or more securing mechanism fromextending beyond a predefined angle relative to the elongate body. 14.The retention device of claim 13 wherein the predefined angle is in therange of about 10 to about 60 degrees.
 15. The retention device of claim11 wherein the retention device comprises silicone.
 16. The retentiondevice of claim 11 wherein the one or more securing mechanisms comprisenitinol, the nitinol adapted to assume a shape above the transitiontemperature thereof that facilitates anchoring in tissue.
 17. Aretention device for use with an implantable medical device (IMD), theretention device comprising an elongate body having a proximal end, adistal end, a hollow lumen extending from the proximal end to the distalend configured to receive a lead of the IMD, the retention devicefurther comprising one or more securing mechanisms having a first endconfigured to bend such that a portion of the one or more securingmechanisms extends to a predefined angle relative to the elongate body;wherein the one or more securing mechanisms includes a second end thatis configured to extend to the predefined angle and push against tissueof a patient; and wherein the elongate body is generally tubular withthe securing mechanisms formed from a cut portion of the tube.
 18. Theretention device of claim 17 wherein the cut portion of the tube islocated between the proximal and distal ends thereof.
 19. The retentiondevice of claim 17 wherein the cut portion of the tube is located at anend thereof.
 20. The retention device claim 17 wherein the one or moresecuring mechanisms comprise nitinol, the nitinol adapted to assume ashape above the transition temperature thereof that facilitatesanchoring in tissue.